Dresden 2003 – wissenschaftliches Programm

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MA: Magnetismus

MA 14: Poster: Schichten(1-31), Spinabh.Trsp.(32-47), Exch.Bias(48-54), Spindyn.(55-64), Mikromag.(65-76), Partikel(77-88), Oflmag.(89-92), Spinelektr.(93-98), Elektr.Theo.(99-103), Mikromag+PhasÜ+Aniso.(104-122), MagnMat.(123-134), Messm+Mol-Mag.(135-139), Kondo(140-151)

MA 14.104: Poster

Dienstag, 25. März 2003, 15:15–19:15, Zelt

Magnetic properties in chromium-chalcogenides systems — •Diana Benea¹, Hubert Ebert¹, Wolfgang Bensch², and Zhong-Le Huang² — ¹Chemistry Department, University Munich, Butenandtstr. 5-13, D-81377 Munich, Germany — ²Institute for Anorganic Chemistry, Olshausenerstr. 40, D-24098, Kiel, Germany

A theoretical investigation of magnetic properties of the systems CrS, CrSe_1−xTe_x and Cr_1+y(Se,Te)₂ is presented. In binary chromium selenides and sulphides Cr has a rather large spin magnetic moment of about 3 µ_B. The exchange interactions are predominanty antiferromagnetic in these compounds, in contrast to the ferromagnetically ordered chromium tellurides. The magnetic phase diagram of the system CrSe_xTe_1−x derived from neutron scattering, show for x=0 − 0.4 ferromagnetic order with magnetic the moments within the basis plane. The alloys with x=0.7 − 1.0 are antiferromagnetic with an umbrella-like non-collinear ordering of the magnetic moments below the Néel temperature. In the region x=0.2 − 0.6 there is a delicate balance between both ferro- and antiferromagnetic ordering with respect to the temperature and concentration.
The magnetic behaviour of the systems has been investigated using the Korringa-Kohn-Rostoker (KKR) band structure method. The disorder in the system has been accounted for by means of the Coherent Potential Approximation (CPA). The magnetic moments and phase stability of these compounds will be discussed.